1. Field of the Invention
This invention relates to the field of bobbin winding apparatus wherein a plurality of strands are to be wound together on a bobbin in a multi-strand band at constant length, and in particular to such an apparatus including a canted Godet wheel, a threading means therefor, and control apparatus for minimizing differences in length while maximizing efficiency of the bobbin winding operation.
2. Prior Art
In winding a plurality of strands on a bobbin to provide a multi-strand band for example to be used in braiding or wrapping a reinforcing sheath for high pressure hose and the like, it is necessary to ensure that during unwinding the bobbin the length of all the strands in the band is equal. If length varies among the strands, the resulting differences in strand tension weaken the braided or wrapped sheath. Winding the multi-strand and on a bobbin involves collecting individual strands from a plurality of sources, normally single-strand spools which are spaced from one another and disposed at differing distances from the winding station such that strands must be brought together from a variety of angles and/or over a variety of linear spans to be wrapped commonly in the band. The supply spools are typically mounted on tensioning mounts, which are individually adjusted to maintain a predetermined tension; however, the precise tension of strands from a plurality of sources normally varies somewhat. In collecting and feeding the individual strands, it is difficult to ensure that the length of the individual strands remains equal.
A known apparatus for equalizing variations in strand length among a plurality of parallel strands is a Godet wheel. A Godet wheel arrangement typically includes two capstans around which fed strands are wrapped for a predetermined number of revolutions, strand length variations among the strands tending to become equalized by a capstan effect as the strands are worked by passage around a common path. In a known multi-strand bobbin winder, the strands from single-strand spools are collected by feeding them through a guide comb onto a capstan, the guide comb positioning the strands at a lateral spacing defined by teeth of the guide comb. Additional guide combs ensure a lateral displacement of the band when passing from one capstan to the other, whereby the band passes helically over each capstan wheel, exiting the paired capstans to be wrapped on a bobbin by means of a feed head which reciprocates parallel to the axis of the bobbin. Typically, a number of combs and idler wheels are encountered by the strands and by the band of strands, for guiding them through changes of direction between their respective source spools and the multi-strand bobbin being wound. These guide combs are a frictional obstruction to equalizing length, and often become the site of a strand break or fouling problem.
Known multi-strand bobbin winding apparatus are also time consuming to set up. The path of the strands through the apparatus must be such that the individual strands remain parallel to define the band, without crossing along the path. Typically, the operator threads the strands through the apparatus individually, pulling each strand end in turn through the guide apparatus, around the capstan to the outlet. The strands are each laid carefully in place, being pulled against the tension of the supply spools. The apparatus must be threaded whenever a supply spool is changed, for example every twenty five bobbins or so (assuming no breakage during winding from a given supply spool). Threading represents a major part of the overall downtime of the apparatus.
If any of the single strand supply spools runs out during the progress of winding a multi-strand bobbin, or if a strand should break, the multi-strand bobbin is reduced substantially to its salvage value. Lengths remaining on individual supply spools which are shorter than a full bobbin length when a companion supply spool runs out are likewise reduced in value. Efficiency requires that all the single strand spools feed a continuous supply during winding and that the supply spool lengths used in winding multi-strand bobbins correspond to an integral multiple of length of the bobbins. Maximizing efficiency in this regard requires keeping track of the supply available from all the supply spools and the amounts expended in winding multi-strand bobbins. According to the present invention, the apparatus used for winding the bobbins, and more particularly the capstan wheels which equalize strand length, are instrumented for management reporting and analysis of the remaining supplies on the supply spools. In this manner, the apparatus can keep a running total of available resources, with appropriate warnings preventing the initiation of a winding operation that cannot be completed.
U.S. Pat. No. 4,154,410--Haehnel et al discloses a multi-strand bobbin winding apparatus wherein strands from individual supply spools are collected and wound over a metering wheel. The strands are positioned using guide combs. The strands lead to the bobbin by way of a reciprocating feeder. The feeder is arranged such that the multi-strand band passes parallel to the bobbin axis from a fixed feeding port to a compensating pulley, then again parallel to the bobbin axis to a reciprocating second pulley, the second pulley reciprocating over the full length of the bobbin for guiding the strand onto the bobbin. The compensating pulley is reciprocated over half the distance that the second pulley is reciprocated, to thereby cancel the effect of the relative variation in feeding speed produced by the fact that the strand is doubled around the compensating pulley. The result is a constant feed rate and constant strand length fed to the bobbin. However, the respective moving parts of the apparatus are engaged to their driving means and to one another by means of belts and gears. The apparatus does not include means for monitoring the available lengths of strand on the respective supply spools, or for relating the available lengths to the usage in winding bobbins.
A bobbin winding apparatus for yarn is disclosed in U.S. Pat. No. 4,462,552--Iannucci. The apparatus includes a pair of capstan or Godet wheels as described above, for equalizing the length of individual strands of yarn when fed in a group defining a band.
U.S. Pat. No. 3,720,054--Haehnel et al; U.S. Pat. No. 3,896,860--Iannucci; U.S. Pat. No. 4,034,642--Iannucci et al; and U.S. Pat. No. 4,729,278--Graeff et al disclose devices for winding strands or bands to reinforce hose and the like, which may be of interest. U.S. Pat. No. 3,839,939--Wily; U.S. Pat. Nos. 3,907,229 and 4,765,220, both to Iannucci et al, disclose tensioning devices for strand spools.
The teachings of each of the noted patents is incorporated herein insofar as they relate to the handling of strands.